Manufacturers of all sizes see an uptick in productivity after adding a factory within a factory via an automated machining cell. The cells are small-scale, clearly defined production units, often for a family of similar parts or a product, and they typically include a robotic arm and one or more machine tools. These can include horizontal and vertical lathes, machining centers and grinders. The cell may also include a conveyor component.
Having this small factory within a factory allows a manufacturer to produce high-volume and high-variety products simultaneously.
In addition to increased productivity and quality, other benefits can include decreased per-unit cost, reductions in scrap, the ability to fill orders by a customer’s deadline, decreased labor costs, enhanced worker safety and efficient use of floor space.
Markische Werk, a German manufacturer of large cylinder head systems, and Husqvarna, a Swedish maker of outdoor power products, both marked productivity gains with the installation of their automated machining cells. So did Wyoming Completion Technologies Inc., which makes tools for downhole work on oil wells, when it found it difficult to find enough workers.
‘They think a robot is complicated...’
When Wyoming Completion first started machining parts in an automated machining cell, President Scott Hecht hoped for a 25-35% boost in production.
“One of the first parts we did on there was a 400% improvement,” he said. “It was shockingly productive.”
Hecht, whose company makes tools used to prepare oil wells for extraction, bought an automated cell with one Okuma GENOS L300 lathe, a bar feeder and a Fanuc robotic arm equipped with iRVision. He worked with Brad Young, of solutions provider Hartwig Inc., and Hartwig’s partner Gosiger Automation on the project.
In Wyoming Completion’s cell, the robot picks up a rough part from a wooden pallet, loads it into the lathe, removes the machined part, and places it on an outbound pallet. For larger part runs, an operator stacks parts on the pallet using plywood sheets to separate any layers. The robot uses a vacuum-equipped end effector to pick up and move the plywood as each layer is completed. Using these hardwood pallets is a simple, cost-effective way to queue up a large number of parts in an automated cell to provide hours of uninterrupted production. As a result, Wyoming Completion runs some of its parts lights out.
Because the system uses Fanuc’s vision system, it requires limited setup from part to part. Typically, all that’s required is to call up the new program and change the part gripper fingers: a five-minute operation.
To increase the cell’s flexibility even more, the robot’s equipped with a Schunk end-of-arm tool system that automatically selects the correct end effector for the chosen program. In addition to the plywood-handling, vacuum-equipped end effector, there’s an end effector for small parts and another for large parts.
Hecht had considered adding a sub-spindle to his Okuma lathe until Young, a sales engineer for Hartwig, suggested spending a little more money to add another lathe.
Hecht decided to add two Okuma LB4000s to the cell Hartwig and Gosiger designed for his operation.
“That is the best machine in the world, and everybody knows it,” Hecht said.
Now instead of buying a large machine with a sub-spindle, he can get more productivity out of the two machines combined with his L300.
The company president can’t say enough good things about his Okuma equipment, Young and the Hartwig team, even though the cell was his first big step into automation, a move he was “scared to death” of making.
“Whenever we do something like that, it’s a big, big deal,” he said.
He had automation built into his machine tools and added bar feeders in some instances, but production hadn’t improved enough to solve a six-month backlog. Once he added his first Okuma lathe, the backlog was taken care of in less than two months.
While Hecht said it’s Young who made the cell work, Young said it’s just the opposite.
“Helping customers overcome challenges is what we do,” Young said. “I knew what to sell them, but they really just jumped in and made it work.”
At one point after the delivery of the equipment, Hecht approached Young and asked if Gosiger could make Wyoming Completion some different grippers and do programing for some additional parts that he wanted to add to the machining cell. Young looked at Hecht, and then at the operator Michael Kvia and said, “You guys can do that yourself.”
Since then, Wyoming Completion contacts Hartwig and Gosiger for advice, but Hecht and his team integrate new processes by themselves.
Part of Wyoming Completion’s success is due to Kvia, both Hecht and Young acknowledged. Not only did he master controlling the robot, he’s now making his own end-of-arm tooling.
Young had been calling on Hecht at Wyoming Completion for some time before proposing the idea of adding an automated machining cell. “He had plenty of machines, but no operators,” Young said. “I brought up automation.”
Powell, population about 6,000, has a challenge faced by factories coast to coast: finding qualified, willing workers.
“I told him he could be 80% efficient,” said Young. “And he didn’t believe me. Nobody does; they think it’s some kind of gimmick. They think a robot is complicated but it’s not.”
Hecht and Young talked a lot about competing with manufacturers in Southeast Asia. Some of what Wyoming Completion manufactures is also manufactured in countries with very low labor rates. But so far Hecht and his team are not only competing but also managing to shut down some competitors from Southeast Asia that had set up operations in the U.S.
Parametric programming helps
While Hecht’s company needed help solving a backlog problem, when you’re the world leader in developing and making cylinder head systems for large combustion engines used in ships, trains and oil and gas plants—like Markische Werk is—productivity is always on your mind.
So, imagine the reaction at Markische Werk in Halver, Germany, when Fastems designed an automated machining cell that increased production of the company’s trumpet-shaped valves by 50%. The cell includes two CNC lathes, a robotic arm to tend batch sizes of 100-600 and two workpiece indexers.
“We had to cope with some challenges in finding a solution,” said factory manager Carsten van Dyck. “First, the turning operation. Second, the insertion of the components into the jaw chuck. And third, the pressing of the components.”
Prior to the installation of the cell, one operator could only tend two machines. Today, one operator can tend three machines, he said.
In addition to the hardware, Fastems set up software with parametric programming for Markische Werk. It eliminates the need to program the robot for the company’s 250 different valve sizes, which range from 170-800mm (6.7-31.5 inches) in length. Instead, the operator who sets up a run can quickly change the part parameters and resume operations.
“I think the key takeaway there is with the software levels that we have installed, the introduction of a new part may take five minutes whereas in the past it may have taken a day or more to hard code in a program,” said David Suica, president of the North American subsidiary of the Finnish company Fastems.
“That’s a big enabler of productivity,” said Teemu-Pekka Ahonen, product manager for Fastems in Issum, Germany.
In addition to the working equipment, Fastems designed the cell to include a roller door between the robot and each machine. When the batch is almost finished, the rest of the run is milled by one machine while the other is prepped for the next lot. Or if one machine needs maintenance, the second lathe can still operate while the issue is evaluated and any repairs can be made safely.
“Without the separation, then the entire cell is down,” Suica said.
He stressed the customized solutions Fastems offers its customers—a process that can take eight months to a year from start to finish depending on the complexity.
“If you’re new to automation, or if a company has an issue … they want to decrease their overhead or they want to have more parts availability, etc., we spend a good bit of our time guiding the customer to help make sure that what we’re developing fits their needs,” he said. “As we work with the customer, we try to guide him in the solution that works for him, not necessarily ‘Well, we have this product and you can buy it’.”
For example, a stateside customer wanted to run lights out over a three-day weekend, so Suica recommended a solution with a larger material buffer capacity.
Critical to the process are the partnerships the company has with makers of the hundreds of brands and models of machine tools that Fastems has integrated into machining cells.
“Our machine tool partners are very important to an automated solution,” Ahonen said. “The better we can agree on the interface and test it together the faster the system commissioning will go.”
Adding cells made plant very productive
While other providers offer custom automated machine tool cells, technology company ABB, maker of robotic arms, has off-the-shelf solutions.
The company has eight standardized, pre-engineered systems under the FlexLoader label that are designed to load and unload machine tools using vision-guided robotics. The robots locate parts in a part queue then pick workpieces from feeder belts or directly from pallets.
Because they’re standardized, ABB’s FlexLoader cells are cheaper and can be gotten quicker than custom cells.
They’re flexible and designed for both small batch and high-volume production.
The FlexLoader cells also increase spindle utilization by up to 60 percent over manual machine tending. The system can handle most any size and type of part and is compatible with a wide range of machine tools, including horizontal and vertical lathes, machining centers, 5-axis machines and grinders.
The different configurations offer flexibility in terms of adding a second robotic arm in a cell, different sized robots to handle various weights of payloads, grippers with a different number of fingers or the ability to handle tubes, the ability to handle workpieces of different sizes, shapes and fragility/toughness and an ability to accommodate different cycle times.
One of the cells is designed to be moveable.
This is beneficial for a customer that needs to process parts through multiple machine tools. For example, the customer’s product would need to be processed through a lathe, then a milling machine. The customer would dock the robot at the lathe for a day, then relocate the robot and dock the robot at the milling machine the next day to complete the machining processes.
The cells facilitate higher machine tool utilization, typically in the range of above 90% compared with manually fed machine tools.
Since 2002, Swedish outdoor power equipment manufacturer Husqvarna, maker of chainsaws, cutting equipment and trimmers, has increased its machine output by installing 29 of ABB’s robotic cells in one of its factories.
The shop has five of ABB’s eight standardized cells from the FlexLoader line: multiples of the FP 300, FP 400, FP 600, FP 800 and SC 6000. They’re used for post-production work including grinding, washing and drilling.
Adding the cells has made this particular plant one of Husqvarna’s most productive.
“Today they have a machine tool tending system with bin pickers and AGVs transporting the components between the different stations and operations,” said Martin Skyborn, product manager for machine tool tending at ABB. “One operator can handle multiple CNC machines due to this solution.”
Husqvarna had already utilized robotics, so using an automated machining cells was a next logical step.
The major problems ABB’s robotic machine tool products solve are providing:
- An easy-to-install, standardized system that can handle a variety of part sizes and shapes without significant retooling;
- Compatibility with all major machining system manufacturers, and
- Consistent quality and improved productivity, while allowing staff members that used to manually tend machine tools to transition to less mundane tasks.
“The installation is fast, just a day or two,” Skyborn said. “And with the standardization, you know what you’re buying is well proven, has good documentation and a high ROI.”